This invention relates to treadmills and, more importantly, to an improved treadmill apparatus which is formed with a deck surface, supported by multiple elastomeric spacers that are resilient enough to minimize shock when the foot of an exerciser contacts the treadmill surface but rigid enough not to interfere with the normal walking, jogging or running motions of the user.
Treadmills utilize an endless moving belt that allows an individual to walk, jog or run in place. Treadmills are useful not only for exercise purposes but also for rehabilitation programs and medical testing such as the popular "stress test." There is also a demand for treadmills in indoor health clubs since many clubs are not able to build a running track and the use of treadmills provides the capability for a well rounded exercise program in smaller health clubs.
Treadmills traditionally are formed with an endless belt which travels over a supporting surface such as a rigid plate so that the belt can withstand the weight of the individual using it. The use of a rigid support plate forms an underlying rigid surface that can create various injuries such as a "stone bruise" or "shin splints" because of its hard, unyielding surface. Another possible way of supporting the belt is to provide rollers under the belt. This construction is not totally desirable because the rollers provide an uneven exercise surface.
Thus, exercising on a treadmill with a rigid support surface underneath the belt is similar to exercising on a hard surface because of the impact on the feet of the user. This tends to exert undue strain on the legs and is a common cause of leg problems for joggers or runners and is particularly bothersome for patients who are undergoing a rehabilitation program.
Several solutions to this problem are set forth in the prior art. For example, U.S. Pat. No. 4,350,336 to Hanford provides a treadmill having a frame to which rollers are attached which carry an endless treadmill belt. The belt moves around a platform disposed beneath the running portion of the belt. The platform is supported by longitudinally oriented platform rails which are supported at the rear end thereof by a lateral frame member which is rigidly secured to the frame. The platform is supported midway along the forward end thereof by a shock absorbing member which is movably attached to the longitudinal rails. The shock absorbing member may be moved longitudinally along the frame to adjust the location of the shock absorbing member. The shock absorbing member in the Hanford device absorbs the shock directly from the platform as a user exercises on the treadmill belt.
In a commercially available device sold by Life Fitness of Franklin Park, Ill., U.S.A., the forward and rear ends of the platform are fixedly connected to the frame of the treadmill with two pairs of rigid elastomeric spacers. A pair of spaced apart shock absorbing members are located along the bottom of a pair of rigid bracket members which extend between each of the platform rails in an effort to cushion the impact of the user's feet on the platform of the treadmill.
The assignee of the present invention has also sold and marketed high end treadmills under the names MEDTRACK and CLUBTRACK for use in physicians'offices and health clubs for many years.
Other known approaches to solving this problem vary from a relatively simple use of an air cell containing surface underneath the treadmill belt as disclosed in U.S. Pat. No. 3,689,066 granted to Hagen to a relatively complex suspension system consisting of various lever arms and shock absorbers as disclosed in U.S. Pat. No. 5,184,988 granted to Dunham.
Another problem related to the use of treadmills arises from the noise and vibrations created during the use of the treadmill. The motors used in most treadmills create a noticeable amount of noise and vibrations during use. This noise and vibration created by the motor may then be magnified by the treadmill deck, particularly in treadmills where the deck is rigidly mounted to the frame of the treadmill. Therefore, the combination of the noise and vibrations created during the use of the treadmill and the noise created by the contact between the feet of the user and the treadmill make the use of treadmills undesirable in many situations.
Despite the foregoing attempts to provide an effective mechanism to cushion the impact of the user's feet on the belt of a treadmill, a need remains for a simple structure which effectively cushions the impact of the user's feet on the belt of a treadmill while also significantly reducing the noise and vibrations created during the use of the treadmill.